AXONAL REGENERATION: a) The presence of glio-axonal transfer of proteins in normal and regenerating axons is investigated by quantitative EM autoradiography in goldfish optic tectum. b) The intra-axonal distribution of 3H glycoproteins transported by axoplasmic flow during axonal regeneration is investigated by quantitative EM autoradiography. c) The capacity of regeneration of peripheral axons into central nervous tissue, and of central axons into peripheral nerves, is studied by grafting (1) a segment of optic nerve into the XII cranial nerve, (2) a segment of the sciatic nerve into the optic nerve in rabbits. Glial Fibrillary Acidic Protein (GFAP), and Neurofilament Protein (NP) in Pathologic Tissues: a) Immunohistochemical localization of GFAP is studied in glial neoplasms. b) Abnormal neuronal fibrillary structures such as fibrillary tangles, Pick bodies are studied by immunochemical methods using NP antisera.